Why does the car still blow hot air when the AC is turned on?

[IvanLee]

Reasons why hot air comes out when the AC is turned on: Overheat protection of the compressor; Overcurrent protection of the compressor; Malfunction of the temperature sensor on the condenser, temperature sensor on the evaporator, or temperature control switch. Below are detailed explanations: Overheat protection of the compressor: If the compressor load is too high (or even if there is too much refrigerant), causing the compressor temperature to rise excessively, it will automatically protect itself and stop working; Overcurrent protection of the compressor: If the compressor load is too high (or if it is stuck due to a fault), or if the generator suddenly provides excessive current, it will trigger the overcurrent protection and stop the compressor from working; Temperature sensor on the condenser: If the external temperature is too high and the AC load is too large, leading to poor heat dissipation and excessive condenser temperature, the signal from the temperature sensor will cause the AC compressor to stop working; Temperature sensor on the evaporator: If it malfunctions, it will send incorrect signals, causing the compressor to stop working. Temperature control switch malfunction: The symptoms are the same as those of a faulty temperature sensor on the evaporator.

[DiMadelyn]

I remember my car had the same issue before, blowing hot air even with the AC on, leaving me sweating. The problem could be in a few areas: refrigerant leak or insufficient refrigerant, the compressor not working or broken, or the thermostat or blend door stuck, constantly blowing hot air. You can check it yourself: first, make sure the temperature setting is at the lowest, not accidentally set to heat; then listen for a humming sound from the compressor in the engine compartment—if there's no sound, the compressor might not be engaging; also, check if the cabin air filter is clogged, as a dirty filter can affect airflow. If these simple checks don't solve the problem, you'll need professional tools to test refrigerant pressure or electrical circuits. It's best to visit a repair shop early to avoid driving in the heat, which could be dangerous and waste fuel. Regular maintenance of the AC system is key—cleaning the filter and inspecting the lines every six months can prevent most issues.

[VonValerie]

From my experience, hot air blowing when the AC is on often involves a malfunctioning blend door stuck in the heating position, or a faulty compressor clutch that fails to engage, refrigerant leaks, or low pressure causing insufficient cooling. It could also be due to incorrect signals sent by the AC control switch. You should check if the blend door operates normally and listen for compressor noise to determine if it's working. If hot air persists despite correct temperature settings, promptly inspect the refrigeration system and test for proper pressure. Ignoring these minor issues may lead to more severe problems, such as complete AC system failure or engine overheating, threatening driving safety. It's advisable to visit a professional repair shop for diagnosis and repairs to ensure efficient AC operation, while also developing regular maintenance habits to extend its lifespan.

[GageLee]

It's really troublesome when the AC blows hot air. Possible causes include thermostat issues or compressor failure. Insufficient refrigerant can lead to poor cooling performance, and a stuck blend door may also cause hot air to blow out. It's necessary to check whether the temperature control settings are correct and if the compressor is functioning. Early repair is recommended to prevent potential hazards.

[PaulDella]

This issue seems common. When hot air comes out with AC on, first try adjusting the temperature setting and switching between recirculation modes. If that doesn't work, it's usually a compressor or control module problem. Regular cleaning of AC components helps prevent malfunctions.

[McKyle]

My friend encountered a similar situation where the AC blew hot air instead. The cause was either a malfunctioning air conditioning control module or a stuck blend door motor, which couldn't distribute the hot and cold air properly. For self-inspection, start by checking the compressor noise. If it's not running, it might be an electrical issue. Simple maintenance like regularly replacing the filter can help prevent such failures.